Hopf oscillator-based gait transition for a quadruped robot

This paper concentrates on the gait transition of a quadruped robot. Animals move with different gaits to adapt to the change of terrains or just to save energy. A biomimetic robot should achieve this process in a smooth, continuous and energy efficient way. We propose a gait transition controller that can achieve needed phase difference between every two legs based on the Hopf oscillator. The quadruped robot has achieved biomimetic gait transitions from walk to trot and trot to gallop based on the proposed controller, and the two gait transitions of the opposite direction are the same by changing the control variables reversely. All of these processes have been verified on a simulated quadruped robot. The robot can achieve a normal velocity value for the walk, trot and gallop gait respectively. Both the walk to trot and trot to gallop gait transitions take only one second. We analyze the stability and some problems existing in the simulation and two gait transitions.